It is often necessary to identify individual wires or circuits which extend between two locations. Please refer to FIG. 1. For example, a typical communication system such as internet service provider system, local area network (LAN) system, wide area network (WAN) system, metropolitan area network (MAN) system, intranet networking system, or telephone work center usually involves in hundreds or even thousands of end users located at different sites or places sharing the service (or controlled by) provided by the same server system 10. Some end users 11 may connect to the server system 10 from the internet 111 through a modern system 112. Some end users 12 may connect to the server system 10 via local servers 121 which may be far away from the server system 10. Some end users 13 may connect to the server system 10 by using hubs 131 which may be located in the same building but different floors of the server system 10. Some end users 14 may connect to the server system 10 through a jack 141 or socket near their working tables. Some end users 15 may use wireless networking devices 151 and wireless hubs 152 to access the server system 10. It is also available or sometimes necessary to connect the server system 10 with another communication system 10a. Most of above mentioned end users require “wires” or “cables” for connection with the server system 10. As a result, the wiring system is concerned. In the wiring system, thousands of wires coming from different locations are gathered and then connected to a distribution frame 20, such like a patch panel stack, before connecting to the server system 10. It is obvious that management of the wires would be a critical issue for such a large wiring system. For example, to identify which jack 211 on the patch panel 21 is connected to which end user located at what remote location. Conventional way to identify wire pairs in the wiring system requires two workers. One worker is stationed at the patch panel stack (distribution frame 20) while the other is stationed at one of the remote end-user locations. The worker at the remote end-user location uses an equipment to generate a test signal to the wires there. The worker at the patch panel stack uses a speaker device and sequentially plugging the speaker device into every jack on the panels until the speaker device is energized by the test signal and generate a test tone. The wire pair which makes the test tone is then identified and labeled. This process is repeated until all wire pairs are identified. It is obvious that such a conventional wire pair identification method is very laboring and time-wasting. In a large wiring system, it may take days or even weeks to perform wire pair identification.
U.S. Pat. No. 5,847,557 disclosed a method to identify wire pairs in a wiring system. Before starting the wire pair identification, each of the jacks on the patch panel stack (distribution frame) is plugged up with an indicator plug which has a LED inside. By applying a test voltage from a remote end-user location, the indicator plug which connects to that remote end-user location is energized and thus the LED inside is driven to light. As a result, the wire pair is identified. Since workers do not need to sequentially scan every patch panel jacks for each remote end-user location jack manually, time consumption and labor cost are reduced. However, there are still deficiencies for the prior art method disclosed in U.S. Pat. No. 5,847,557. For example, it requires workers to apply lots of indicator plugs to every one of the jacks on the patch panel stack before starting to apply the test voltage, and to remove all of the indicator plugs after the wire pair identification process is completed. Time waste still exists. In addition, it is impossible for U.S. Pat. No. 5,847,557 to directly built-in the LEDs inside the jacks of the patch panel because the LED circuit will incur a short circuit between two contacts of the jack. And, once the patch panel stack is under normal operation such as transmission of communication signals, the LED circuit will result in “loop back shorting” and seriously disrupt the communication. Therefore, it leaves a room for further improvements.